Numerous environmental toxicants have been shown to induce the epigenetic transgenerational inheritance of disease and phenotypic variation. Alterations in the germline epigenome are necessary to transmit transgenerational phenotypes. In previous studies, the pesticide DDT (dichlorodiphenyltrichloroethane) and the agricultural fungicide vinclozolin were shown to promote the transgenerational inheritance of sperm differential DNA methylation regions, non-coding RNAs and histone retention, which are termed epimutations. These epimutations are able to mediate this epigenetic inheritance of disease and phenotypic variation. The current study was designed to investigate the developmental origins of the transgenerational differential histone retention sites (called DHRs) during gametogenesis of the sperm. Vinclozolin and DDT were independently used to promote the epigenetic transgenerational inheritance of these DHRs. Male control lineage, DDT lineage and vinclozolin lineage F3 generation rats were used to isolate round spermatids, caput epididymal spermatozoa, and caudal sperm. The DHRs distinguishing the control versus DDT lineage or vinclozolin lineage samples were determined at these three developmental stages. DHRs and a reproducible core of histone H3 retention sites were observed using an H3 chromatin immunoprecipitation-sequencing (ChIP-Seq) analysis in each of the germ cell populations. The chromosomal locations and genomic features of the DHRs were analyzed. A cascade of epigenetic histone retention site alterations was found to be initiated in the round spermatids and then further modified during epididymal sperm maturation. Observations show that in addition to alterations in sperm DNA methylation and ncRNA expression previously identified, the induction of differential histone retention sites (DHRs) in the later stages of spermatogenesis also occurs. This novel component of epigenetic programming during spermatogenesis can be environmentally altered and transmitted to subsequent generations through epigenetic transgenerational inheritance.

许多环境毒物已被证明可诱导疾病和表型变异的表观遗传跨代遗传。种系表观基因组的改变是传递跨代表型所必需的。在之前的研究中，农药滴滴涕（二氯二苯基三氯乙烷）和农用杀菌剂万氯唑啉被证明可以促进精子差异 DNA 甲基化区域、非编码 RNA 和组蛋白保留的跨代遗传，这些被称为表观突变。这些表观突变能够介导疾病的表观遗传和表型变异。目前的研究旨在调查精子配子发生过程中跨代差异组蛋白保留位点（称为 DHR）的发育起源。Vinclozolin 和 DDT 被独立用于促进这些 DHR 的表观遗传跨代遗传。雄性对照谱系、DDT谱系和vinclozolin谱系F3代大鼠用于分离圆形精子细胞、附睾头精子和尾部精子。在这三个发育阶段确定了区分对照与 DDT 谱系或 vinclozolin 谱系样品的 DHR。使用 H3 染色质免疫沉淀测序 (ChIP-Seq) 分析在每个生殖细胞群中观察到 DHR 和可重现的组蛋白 H3 保留位点核心。分析了 DHR 的染色体位置和基因组特征。发现在圆形精子细胞中开始了一系列表观遗传组蛋白保留位点改变，然后在附睾精子成熟过程中进一步改变。观察表明，除了先前发现的精子 DNA 甲基化和 ncRNA 表达的改变外，在精子发生的后期也会发生差异组蛋白保留位点 (DHR) 的诱导。精子发生过程中表观遗传编程的这一新组成部分可以通过表观遗传跨代遗传来改变环境并传递给后代。